This disclosure relates to composite articles, such as those used in gas turbine engines.
Components, such as gas turbine engine components, may be subjected to high temperatures, corrosive and oxidative conditions, and elevated stress levels. In order to improve the thermal and oxidative stability of these components, the component may include one or more of a protective environmental barrier, thermal barrier, velocity barrier, erosion resistant, or abradable coating. The protective coating may be a multi-layer coating that includes a top coat and a bond coat beneath the top coat to adhere the top coat to the underlying substrate.